The present invention relates to a passive antiroll device for the suspension of a motor vehicle comprising a torsion bar and two lateral links connected to this bar and to two lateral shock absorbers of the suspension, as well as such a suspension incorporating this antiroll device.
In a known manner, front and/or rear axle suspension systems of current motor vehicles are fitted with antiroll devices which can be active (i.e. using an electronic control which modifies the characteristics of the suspension, typically via a hydraulic control) as described for example in the document DE-A-10 2005 028 327, or passive (i.e. without a power supply) as described for example in the document WO-A-03/008215.
Passive antiroll devices usually comprise a U-shaped torsion bar (also called a stabilizer bar) of which the central portion is connected to the chassis of the vehicle and of which the two curved ends are respectively connected by rigid links to the suspensions fitted to the wheels of the axle concerned. These known passive devices, such as the one in the document WO-A-03/008215, usually have a satisfactory antiroll stiffness, due to the fact that the torsion bar immediately tends to twist when one of the two wheels moves vertically in relation to the other (for example on a curve or during banked driving), this torsion thus generating a stiffness which is added to that of the shock absorber springs.
However, a major disadvantage of these passive antiroll devices lies in the fact that when one of the wheels of the axle concerned encounters a raised or recessed obstacle while driving in a straight line, the vibration received from the shock absorber concerned is transmitted via the rigid link to the torsion bar, then to the chassis of the vehicle, thus generating a source of discomfort for the passengers of the vehicle. In addition, these known devices not only couple each wheel of the axle concerned to the chassis via the torsion bar but also couple the two wheels to each other, which is also a source of discomfort for the passengers. Consequently, these known passive devices give satisfaction for the roadholding of the vehicle, but to the detriment of the comfort in the passenger compartment.
An object of the present invention is to provide a passive antiroll device for the suspension of a motor vehicle which overcomes this disadvantage, this device comprising a torsion bar and two lateral links respectively articulated, on the one hand, to the two ends of the torsion bar by two first hinges and, on the other hand, to two lateral shock absorbers of the suspension by two second hinges, at least one of the said links, or telescopic link, including a piston slidably mounted in a piston tube by means of a rod which carries this piston and which is connected to the said second connection, the piston being able to slide reversibly due to the movement of the said second connection and cooperating in compression with return means housed inside the said tube.